1. Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, Albert-Einstein-Straße 15, D-07745 Jena, Germany
2. Chair of Energy Process Engineering, TU Bergakademie Freiberg, Fuchsmühlenweg 9D (Reiche Zeche), D-09599 Freiberg, Germany
3. Fraunhofer Institute for Applied Optics and Precision Engineering IOF Jena, Albert-Einstein-Straße 7, D-07745 Jena, Germany